The present invention relates generally to a radar system and, more particularly, to a warning radar that may be used to detect obstacles in the path of a moving or stationary vehicle. Although the present invention will be described herein primarily with regard to a vehicle obstruction warning radar, it should be understood that the present invention may also be also be used in other applications. For instance, the present invention may be used in other similar or conventional applications of radars.
A driver may check his rearview mirror and sideview mirrors when backing up a vehicle. A driver may also pivot his head around to look behind the vehicle. Despite checking each of the mirrors and/or turning around, there typically is a blind spot in the driver's field of view. Compounding the problem with the blind spot, some drivers may not see properly behind the vehicle simply because they are distracted or do not exercise proper care. As a result, a driver may not see obstacles behind the vehicle when backing up. For many of the same or similar reasons, a driver may not be able to see obstacles located to the side or front of a vehicle.
In light of the difficulties with seeing obstacles when driving a car, there is a need for a radar system that detects and warns of such obstacles. There is also a need for a radar system that can accurately detect the presence of an obstacle using one or more transmitted signals of substantially the same frequency as opposed to multiple transmitted signals having different frequencies. Furthermore, a need exists for being able to determine the presence of an obstacle without modulating the transmitted signals.
The present invention solves one or more of the aforementioned needs. The system includes at least one transmitting antenna and at least one receiving antenna. In one exemplary embodiment which includes multiple transmitting and/or receiving antennas, the receiving antennas may be arranged in at least one linear array to provide spatially distributed data to facilitate the determination of the angle and range estimates of the obstacle(s). It should be recognized that the receiving antennas may be arranged in a non-linear configuration, but a non-linear configuration may increase the difficulty of determining the angle and range estimates of the obstacles.
The transmitting antenna receives an input signal and transmits an electromagnetic wave. The electromagnetic wave reflects off an obstacle back to the receiving antenna. The receiving antenna captures the reflected electromagnetic wave and produces an output signal. The output signal is then combined with the input signal in a quadrature mixer. The resulting in-phase (I) and quadrature (Q) signals may be further processed and then transmitted to a processing system. The processing system uses a suitable algorithm (e.g., a near field back projection algorithm, a far field angle of arrival algorithm, or any other type of tomographic algorithm) to estimate the type and/or location of obstacle that reflected the electromagnetic wave. In an exemplary embodiment, the algorithm is adapted to discriminate between different sizes and/or locations of obstacles in order to determine if there is a hazard. Based on this information, the processing system may then communicate with a visual or audible display or warning system in order to alert the driver about the obstacle if it has been determined to be a hazard.
In addition to the novel features and advantages mentioned above, other objects and advantages of the present invention will be readily apparent from the following descriptions of the drawings and exemplary embodiments.